1. Field of the Invention
The present invention relates to a thermoplastic resin composition with superior flame retardancy, colorability and scratch resistance. More particularly, the present invention relates to a thermoplastic resin composition which exhibits flame retardancy, impact strength, scratch resistance, colorability and surface hardness based on a synergistic effect through incorporation of a bromine organic flame retardant and a coated antimony compound in a resin containing an acrylonitrile-butadiene-styrene copolymer.
2. Description of the Related Art
In general, an acrylonitrile-butadiene-styrene (hereinafter, referred to as ABS) resin is widely used as exterior materials of electric/electrical products and office machines and the like due to stiffness and chemical resistance of acrylonitrile, and processability and mechanical strength of butadiene and styrene. However, the ABS resin is inherently combustible and is vulnerable to fire.
Due to these problems, the ABS resin used for electric/electrical products, office machines and the like should satisfy flame-retardancy standards in order to secure safety against flames. Methods for imparting flame retardancy to ABS resins include polymerization of rubber-modified styrene resins through incorporation of flame retardant monomers, mixing a flame retardant and a flame retardant aid with the prepared rubber-modified styrene resin and the like.
The flame retardants may be classified into halogen flame retardants and non-halogen flame retardants. The non-halogen flame retardants should be added at a relatively greater amount due to considerably low flame retardancy efficiency, as compared to halogen flame retardants, thus causing deterioration in mechanical and physical properties of rubber-modified styrene-based resins.
Accordingly, the most general method for imparting flame retardancy to an ABS resin is to use a halogen flame retardant. The halogen flame retardant is effective in improving flame retardancy, while maintaining mechanical and physical properties of a rubber-modified styrene resin. In particular, a bromine flame retardant is particularly effective. However, the ABS resin to which flame retardancy is imparted has considerably low scratch resistance due to inherent butadiene rubber characteristics of the ABS resin and ABS resin products with high gloss are disadvantageously readily scratched.
Meanwhile, a flame retardant aid does not exhibit complete flame resistance, but has improved flame resistance effects, when used in conjunction with a flame retardant, thus advantageously reducing a content of the flame retardant. Generally, in a case in which a halogen flame retardant is used, use of an antimony compound as a flame retardant aid is particularly effective.
However, when a flame retardant ABS resin is prepared from a conventional antimony trioxide compound, problems such as deterioration in physical properties, for example, impact strength and colorability of the resin occur. The antimony trioxide compound also has regulatory issues such as prohibition or restriction of use thereof due to risk and negative effects on the human body and environment. In addition, most flame retardant ABS resins have a scratch resistance, measured as pencil hardness, of 3B or 4B.
Accordingly, there is increasing demand for development of ABS resins which maintain superior scratch resistance, impact strength and flowability, and exhibit superior flame retardancy.